Aussie singer-songwriter Sia is writing and directing a new film project called Sister, which will star her regular collaborator and dancer Maddie Ziegler.

As The Hollywood Reporter reports, Sia has spoken through her trademark blonde wig at Venice Days (a sidebar of Venice Film Festival) to share some details about Sister.

The film is reportedly based on a one-page story Sia wrote about eight years ago, and the idea for the project seems to have been churning over in her mind for some time.

“I was too embarrassed to tell anyone I wanted to make a movie, because I thought it would be seen as a vanity project, because I was a singer,” Sia says.

“And then last year after I made the Chandelier video, I realised that I was pretty good at directing, so I felt a little bit braver.”

Sia isn’t going it alone, though, and has worked with some film creatives to fine-tune her idea. “So first I paid a guy from a juice bar to help me write it, who had gone to film school, and it turned out it wasn’t quite right,” she says.

Sia then turned to another friend, children’s book author Dalles Clayton. “He and I spent three-and-a-half weeks just on the sofa, mapping it out,” she says.

In developing her film project, Sia has seen some similarities between film-making and her songwriting process. “For me, the process was basically, ‘I work out the movie. I’ll act it out, I’ll have the dialogue already in my head,’” she says.

“It’s really the formatting… I can’t be bothered to learn Final Draft. I’m not a technical person. Like, when I sing, I just want to sing the melody and write the lyrics.

“I don’t want to have to do production, which is very technical. I don’t enjoy that. What I do enjoy is the creative process.”

Before the Sister script is finalised, Sia’s notes are being fine-tuned by Clayton. The notes have already had a good looking-over from comedian Whitney Cummings, actor Joel Edgerton and Sia’s husband Erik Anders Lang, who apparently “gave the best notes”.